Various types of diseases are caused by muscle damage or atrophy, or by muscle reduction or deficiency due to inadequate development, such as sarcopenia, steroid myopathy and muscular dystrophy. Sarcopenia is a syndrome induced by muscle reduction with aging. Development of therapeutic approaches for sarcopenia has become an important health issue for elderly people. Along with kinetic or dietary treatments, treatment and prevention by medicines are prospective means for alleviating the symptoms of sarcopenia. Further, for patients who are suffering significant muscle reduction, use of medicines to enhance their muscles and enable them to take exercise is a beneficial measure.
As medicines for sarcopenia, a substance that inhibits the activity of myostatin, which is a negative regulator of myogenesis (see, for example, the Japanese translation of PCT International Application Publication No. 2008-530004), and a Fbxo40 antagonist that inhibits insulin receptor substrate 1 (IRS1) that induces myogenesis (see, for example, the Japanese translation of PCT International Application Publication No. 2013-519869) have been proposed. However, these proposals have not yet led to practical applications.
Meanwhile, there have been reports on several research outcomes regarding the relationship between the activity of TAZ, which is a transcriptional coactivator, and the formation and differentiation of skeletal muscles (see, for example, FASEB J 24: 3310-3320 and Biochem. Biophys. Res. Commun. 339: 533-539). These reports suggest that a substance that activates TAZ may promote formation and differentiation of skeletal muscles. As the substances that activate TAZ, a phenyltetrazole derivative (see, for example, Japanese Patent Application Laid-Open No. 2010-280658), kaempferol (see, for example, Bone 50: 364-372) and TM-25659 (see, for example, Br. J. Pharmacol. 165: 1584-1594) are known.